How can I animate an edge loop?
You may do this using Shape Keys.


Being in Object Mode go to the Data header and in a Shape Keys panel add a key (press the '+' button) and name it location. Enable the apply shapekeys in edit mode option. Now enter the Edit Mode, change the location key value to 1 and slide your edge loop along the object. Next set the location key value back to 0.


Go to frame 1 on your timeline, hover your cursor over the Value slider in a Shape Keys panel and press I to insert a keyframe.


Go to the next desired frame on your timeline, change the shapekey Value to 1 and press I again.


Now insert the keyframe for rotation. Being in Object Mode, in 3D window go to frame 1 and press I-->LocRotScale (or just Rotation).


Go to the next desired frame on your timeline, rotate your object (R) and press I-->LocRotScale again.


If you want a constant movement of your animation go to the Graph Editor, press T and change the keyframe interpolation type to Linear.


Remember, that you can change the duration of inserted keyframes animation. Go to the Dope Sheet Editor, select the desired action and place it (using G) wherever you like on a timeline. In my case I've increased the green gauge speed.